Improvement in steam-boilers



NITRD STATES ATRNT OFFICE.

B. H. BARTOL, OF PHILADELPHIA, PENNSYLVANIA.

IMPROVEMENT IN STEAIVIFBOILERS.

Specification forming part of Letters Patent No. 34,556, dated March 4L, 1862.

` and I do hereby declare the following to be a `full, clear, and exact description of the saine,

reference being had to the accompanying' drawings, and to the letters of reference marked thereon.

My invention consists of a furnace di ving- .iiue, one or more horizontal fines, and a return-[lue with vertical tubes, the whole being arranged within an extericr shell or casing, in the manner described hereinafter, so that. the boiler may be reduced in height and used on gun-boats of light draft without being exposed to an eneinys shot.

In order to enable others skilled in the art to make my invention, I will now proceed to describe the manner of constructing the same.

On reference to the accompanying drawings, which form apart of this specification, Figure l is a vertical section of my improved steamboiler for marine engines ;`Fig. 2, a transverse vertical section of part of the boiler on the line l 2, Fig. l; and Fig. 3, a transverse section ou the line 3 L, I `ig. l.

Similarletters refer to similar parts throughout the several views.

A is the exterior casin g or shell of the boiler; B, the furnace; C, the arched top of the same; D, an opening, to one edge of which is hinged the usual door; E, the ash-pit; G, the bridge; F, the grate-bars; H, the diving-flue at the rear of the bridge, and I the lower water-space continued throughout the entire length of the boiler.

One or more round or oval iiues, J, form a communication between the divin g-tlue H and smoke-chamber K, which communicates with the return-flue M, the latter being separated from the lower flue, J, by the water-space L and communicating through the iiue N with the chimney.

Vithin the return-flue M are arranged a series of vertical tubes, a, which form a communication between the water-space L and the space above the return-flue, the level of the water being represented by the line Boilers with return-fines situated directly above the fire-box and containing a series of vertical or nearly vertical tubes have been in common use, a boiler of this .description having been invented by Lord Dundonald and described in vol. 53, page 466, of the London Mechanics Magazine for 1850, and subsequently reproduced by D. B. Martin, to whom Letters Patent of the United States were granted November 2S, 1854. Although boilers of this class have been adopted to a considerable extent in the larger class of vessels of the United .States Navy, for the reason that they occupy comparatively small space as regards length and width in the hold of a vessel, they are not well adapted to war-vessels of light draft, as the arrangement of the tubular fines directly above the furnace involves the necessity of making vthe boiler so high that the upper portion is prominently exposed to the shots of an enemy. v

By arranging the tubular ue M at the rear of and nearly as low down as the furnace the boiler is so far reduced in heightas to be contained in the hold of a vessel of light draft and free from exposure to the effects of an enemys shots, thus rendering it especially applicable to light gun-boats, in which the area occupied by the boiler is of little importance compared with the reduced height, which insures the desired protection. l I claim as my invention and desire to secure by Letters Patent- The furnace B,'diVing-flue II, one drang;

horizontal fines, J, and the return-flue M, wit i\ V its vertical tubes, the whole being arranged within the casing A, as for the purpose herein set forth.

In testimony whereof I have signed my name to this specification in the presence of two subscribing. witnesses.

B. H. BARTOL.

Vitnesses:

HENRY HowsoN, CHARLES E. FOSTER. 

